1. Field of Invention
The invention relates to an information sensing device, which can be an image sensor, a fingerprint sensor, a vein sensor or other sensors, and a method of manufacturing the same, and more particularly to an information sensing device capable of preventing electrostatic discharge damage and a method of manufacturing the same. The information sensing chip of the invention can be found in the commonly assigned patent applications: (a) U.S. patent application Ser. No. 10/403,052, filed on Apr. 1, 2003, entitled “CAPACITIVE FINGERPRINT SENSOR”, and issued on Aug. 29, 2006 as U.S. Pat. No. 7,099,497; (b) U.S. patent application Ser. No. 10/434,833, filed on May 13, 2003, entitled “PRESSURE TYPE FINGERPRINT SENSOR FABRICATION METHOD”, and issued on Jul. 6, 2004 as U.S. Pat. No. 6,759,264; (c) U.S. patent application Ser. No. 10/414,214 (US20040208345A1), filed on Apr. 16, 2003, and entitled “THERMOELECTRIC SENSOR FOR FINGERPRINT THERMAL IMAGING”; (d) U.S. patent application Ser. No. 10/638,371 (US20040046574A1), filed on Aug. 12, 2003, and entitled “CAPACITIVE MICRO PRESSURE SENSING MEMBER AND FINGERPRINT SENSOR USING THE SAME”; and (e) Taiwan Patent Application No. 090112023, filed on May 17, 2001, and entitled “CAPACITIVE PRESSURE MICROSENSOR AND METHOD FOR MANUFACTURING THE SAME AND DETECTING SIGNALS OF THE SAME”, now published as TW541503 and issued as Invention Patent Number 182652.
2. Related Art
A conventional semiconductor chip after being packaged has to be tested in the aspect of electrostatic discharge to ensure that the product design cannot be damaged due to the typical electrostatic discharge. The discharge modes include an air mode and a contact mode. The contact mode is a more severe mode for testing the electrostatic discharge. A probe has to contact with an electroconductive portion of a package body to perform the electrostatic discharge test.
Taking a fingerprint sensor as an example, the semiconductor information sensing chip has to provide an exposed chip surface to contact with the finger. The chip surface exposed to the environment tends to be interfered by some external effects, such as the grease and the remained contamination of the finger, and tends to be damaged by the electrostatic discharge to cause a serious problem.
In order to make the exposed chip surface of the package body (e.g., the fingerprint sensor) pass the electrostatic discharge test of the contact mode, the conventional method is to form an exposed metal layer on the chip surface to conduct the electrostatic charge, which approaches the chip surface, to the ground of the system. This aspect cannot pass the test standard in the electrostatic discharge of the severe contact mode. This is because an electroconductive metal layer of the chip surface is too close to a bottom integrated circuit, and the electromagnetic wave of the electrostatic discharge test may latch up the integrated circuit so that the chip cannot work normally or is damaged permanently.
In another aspect, a metal housing may be provided to cover the package body so that the electrostatic charge can be grounded through the metal housing. However, the assembling process is time-consuming and labor-consuming, and the manufacturing cost is increased. In addition, the metal housing may drop during the post processing steps, such as a SMT process.
Thus, it is an important subject of the invention to provide a semiconductor device, which has the reduced manufacturing cost and is advantageous to the automatic production, and a method of manufacturing the same.